Effect of Digital Cameras on Zoom Ranges

Archived from groups: rec.photo.digital (More info?)

Jules wrote:
> Hi all,
>
> I have just treated myself to a Pentax *ist DS having used an MZ30 for
> several years fitted with a Pentax FA 28-200 zoom lens. This lens is not
> designed specifically for digital cameras but the *ist DS contacts support
> this lens. However does anybody no whether the zoom of this lens will be
> changed? I have a vague recollection of seeing something that this lens on a
> digital camera would be changed to something like 35-207.

The zoom won't be changed, it's still the same overall range (about 7X),
but because the camera's sensor is smaller than a 35mm film frame, it
crops part of the frame, and you get the equivalent coverage of a longer
lens. 1.6 is one of the more common crop factors; it means that a 28mm
lens will cover the same area as a 45mm would (28 x 1.6) on standard
35mm film.

Archived from groups: rec.photo.digital (More info?)

thanks mat


"Matt Ion" <soundy@moltenimage.com> wrote in message
news:QMosd.430244$nl.241559@pd7tw3no...
> Jules wrote:
>> Hi all,
>>
>> I have just treated myself to a Pentax *ist DS having used an MZ30 for
>> several years fitted with a Pentax FA 28-200 zoom lens. This lens is not
>> designed specifically for digital cameras but the *ist DS contacts
>> support this lens. However does anybody no whether the zoom of this lens
>> will be changed? I have a vague recollection of seeing something that
>> this lens on a digital camera would be changed to something like 35-207.
>
> The zoom won't be changed, it's still the same overall range (about 7X),
> but because the camera's sensor is smaller than a 35mm film frame, it
> crops part of the frame, and you get the equivalent coverage of a longer
> lens. 1.6 is one of the more common crop factors; it means that a 28mm
> lens will cover the same area as a 45mm would (28 x 1.6) on standard 35mm
> film.

Archived from groups: rec.photo.digital (More info?)

Darrell,

Having had a chance to digest your post are you saying that:

My lens on a 35mm film camera body will have a zoom range of 28-200mm but
the same lens on the *ist DS camera body would have the same zoom range as a
42-300mm zoom mounted on a 35mm film camera body and conversely a 42-300mm
zoom lens specifically designed for use on an *ist DS camera body would have
the same zoom range as my 28-200mm mounted on the *ist DS camera body?

Thanks for the advice

Jules


" Darrell Larose" <no@spam.here> wrote in message
news:TY6dnRAZxf1L8y_cRVn-ow@rogers.com...
>
> "Jules" <j.pike@bigfoot.com> wrote in message
> news:juosd.406$zX5.297@newsfe2-gui.ntli.net...
>> Hi all,
>>
>> I have just treated myself to a Pentax *ist DS having used an MZ30 for
>> several years fitted with a Pentax FA 28-200 zoom lens. This lens is not
>> designed specifically for digital cameras but the *ist DS contacts
>> support
>> this lens. However does anybody no whether the zoom of this lens will be
>> changed? I have a vague recollection of seeing something that this lens
>> on
> a
>> digital camera would be changed to something like 35-207.
>>
>> Grateful for any thoughts
>>
>> Jules
>>
> The lens will remain a 28~200, digital won't change that. The FOV (Field
> of
> View) crop is 1.5x with Pentax * ist D and * ist DS. the FOV of 1.5x so
> the
> lens will look like a 42~300 on a film 35mm SLR. Simply put, because of
> the
> smaller sensor size you are effectively making an 8x12" print and cutting
> the central 5x7.5" from the middle...
>
>